Myš
Moderátor: Moderátoři
How Microsoft (tm) mouse works
The mouse connects to any RS232 serial port (COM1, 2, etc.). In its basic form, it uses only RX (PC side) and GND to communicate, while the RTS (sometimes coupled with TX) line is used as a power source to feed mouse circuitry. Every time you move the mouse, or just press or release a button, three bytes are sent over the serial line at a speed of 1200 baud, 8 data bits, no parity, two stop bits.
..........MSB= B7....B6....B5....B4....B3....B2....B1....B0=LSB
first byte........1......1......L......R.....Y7....Y6....X7....X6
second byte...1......0.....X5....X4....X3....X2....X1....X0
third byte.......1......0.....Y5.....Y4....Y3....Y2....Y1....Y0
L and R are the status of the left and right buttons, 0 = released and 1 = pressed. X7..X0 and Y7..Y0 are the binary digits of the X and Y counters. They hold the number of X and Y steps from last transmission. This makes the mouse a relative encoder, that is there is no "zero" or absolute position as every movement is relative to the last position transmitted.
The mouse connects to any RS232 serial port (COM1, 2, etc.). In its basic form, it uses only RX (PC side) and GND to communicate, while the RTS (sometimes coupled with TX) line is used as a power source to feed mouse circuitry. Every time you move the mouse, or just press or release a button, three bytes are sent over the serial line at a speed of 1200 baud, 8 data bits, no parity, two stop bits.
..........MSB= B7....B6....B5....B4....B3....B2....B1....B0=LSB
first byte........1......1......L......R.....Y7....Y6....X7....X6
second byte...1......0.....X5....X4....X3....X2....X1....X0
third byte.......1......0.....Y5.....Y4....Y3....Y2....Y1....Y0
L and R are the status of the left and right buttons, 0 = released and 1 = pressed. X7..X0 and Y7..Y0 are the binary digits of the X and Y counters. They hold the number of X and Y steps from last transmission. This makes the mouse a relative encoder, that is there is no "zero" or absolute position as every movement is relative to the last position transmitted.
